Pre-treatment of composite industrial wastewater by Fenton and electro-Fenton oxidation processes

Abstract

The present study aims to characterize three industrial wastewater samples collected from petrochemical, food and beet sugar industries to determine the pollution potential and select the appropriate pre-treatment approach. According to the biodegradability profile of the multi-sourced mixed samples, the advanced oxidation process (AOPs) namely, Fenton (F) and Electro-Fenton (EF) were adopted as pre-treatment techniques and the operating parameters such as, time, type of electrodes, pH, voltage, iron and H2O2 concentrations were critically examined. Analysis of Variance (ANOVA) was conducted to compare the performance efficiency of F& EFAOPs for treating the composite samples. The results revealed that initial values of the composite samples were 7.11, 19.2, 32.6, 19.3, 937, 1512, 860, 3.9, 2110 and 2.34 for pH, Total Dissolved Solids (TDS), Electrical Conductivity (EC), Salinity, BOD, COD, Oil and grease (O&G), Total Phosphorous (TP), Total suspended Solids (TSS) and Total Kjeldahl Nitrogen (TKN), respectively. In addition, electro-Fenton process achieved removal efficiency for COD, O&G, BOD, TSS, and TKN, by 84.3%, 69%, 85%, 72% and 71.27% compared to Fenton which displayed 78.43%, 66%, 69%, 70.1%, and 61%, respectively. Consequently, there are statistically significant differences between the initial and final (pretreated) values of the composite wastewater for the addressed parameters and the EF process was significantly more effective than F. It was concluded that both Fenton and electro-Fenton processes are favorable, eco-friendly and cost-effective options for pretreating real complicated mixed multi-sourced industrial wastewater.